Free hot water

Use free solar radiation to heat a gallon of water for washing up, doing dishes or whatever. Put the water in a glass jar and set it in the sun for a few hours. Don't set it on concrete or other hard surface and not in the snow. If you can put it where there is a dark surface behind it, it will heat better. You may be surprised at how warm it gets.

Free hot water

A barrel or bucket painted black or other dark color, filled with water and set in the sun (even in the winter) will absorb enough solar rays to heat hot enough to wash dishes, do laundry, or even bathe. It may take a few hours, so keep an eye on it and move it if necessary to keep it in the sunshine. Alternatively, stretch a long hose across a sunny lawn (even on a warm winter day as long as you keep it up out of snow) will heat water in a few hours.